The present patent application claims priority from Japanese patent applications Nos. H. 11-139683 filed on May 20, 1999, H. 11-147538 filed on May 27, 1999 and H. 11-256522 filed on Sep. 10, 1999, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a liquid container equipped with a piezoelectric apparatus therein which detects the consumption state of liquid inside a liquid container which houses the liquid. More particularly, the present invention relates to the liquid container equipped with a piezoelectric apparatus that detects liquid consumption status in a liquid container which provides liquid to a recording head of an ink-jet recording apparatus.
2. Description of the Related Art
An ink cartridge mounted on an ink-jet type recording apparatus is taken as an example of a liquid container and is described below. In general, an ink-jet recording apparatus comprises: a carriage equipped with an ink-jet type recording head comprised of a pressure generating means which compresses a pressure generating chamber and a nozzle opening which discharges the compressed ink from a nozzle opening in the form of ink droplets; and an ink tank which houses ink supplied to the recording head through a passage, and is structured such that the printing operation can be performed continuously. In general, the ink tank is structured as a cartridge that can be detached from the recording apparatus, so that a user can easily replace it at the time when the ink is used up.
Conventionally, as a method of controlling the ink consumption of the ink cartridge, a method is known of controlling the ink consumption by means of a calculation in which the counted number of ink droplets discharged by the recording head and the amount of ink sucked in a maintenance process of the printing head are integrated by software, and another method of controlling the ink consumption in which the time at which the ink is actually consumed is detected by directly mounting to the ink cartridge two electrodes for use in detecting the liquid surface, and so forth.
However, in the calculation-based method of controlling the ink consumption by integrating the discharged number of ink droplets and the amount of ink or the like by the software, the pressure inside the ink cartridge and the viscosity of the ink change depending on usage environment such as ambient temperature and humidity, elapsed time after an ink cartridge has been opened for use, and usage frequency at a user side. Thus, a problem is caused where a considerable error occurs between the calculated ink consumption and the actual ink consumption. Moreover, another problem is caused in which the actual amount of ink remaining is not known because once the same cartridge is removed and then mounted again, the integrated counted value is reset.
On the other hand, in the method of controlling by electrodes the time at which the ink is consumed, the remaining amount of ink can be controlled with high reliability since the actual ink consumption can be detected at one point. However, in order that the liquid surface of the ink can be detected, the ink need be conductive, so suitable types of ink for use are very limited. Moreover, a problem is caused in that a fluid-tight structure between the electrodes and the cartridge might be complicated. Moreover, since precious metal is usually used as the electrode material, which is highly conductive and erosive, manufacturing costs of the ink cartridge increases thereby. Moreover, since it is necessary to attach the two electrodes to two separate positions of the ink cartridge, the manufacturing process increases, thus causing a problem which increases the manufacturing costs.
Moreover, when managing the ink consumption status by mounting a piezoelectric device on the ink cartridge, ink inside the ink cartridge may roll or bubble by the scanning of the ink cartridge during the printing operation. By the waving or bubbling of ink near by the piezoelectric device, ink or bubble of ink attaches to the piezoelectric device. Then, there is a cases arises that the piezoelectric device cannot detect the ink consumption quantity by the ink or bubble of ink attached to the piezoelectric device. In other words, even there is only small amount of ink inside the ink cartridge, if the ink attaches to the piezoelectric device mistakenly by the waving of ink, there is a danger that the piezoelectric device detects mistakenly that there is still enough ink inside the ink cartridge. Moreover, if the bubble attaches to the piezoelectric device, there is danger that the piezoelectric device detects mistakenly that there is no ink inside the ink cartridge even if the ink cartridge 180 is filled by ink.
Furthermore, there is problem that the position of mounting the piezoelectric device on the ink cartridge is limited for detecting the ink end status in side the ink cartridge. For example, if mounting the piezoelectric device on the wall at the lower side of the ink surface, the piezoelectric device can detect the ink end. On the other hand, if mounting the piezoelectric device on the wall at the upper side of the ink surface, the piezoelectric device cannot detect the ink end.
Therefore, it is an object of the present invention to provide a liquid container capable of reliably detecting a liquid consumption status and dispensing with a complicated sealing structure.
Moreover, it is another object of the present invention to prevent the waving or bubbling of liquid around the piezoelectric device inside the liquid container.
Furthermore, it is still another object of the present invention to provide a liquid container, the piezoelectric device of which can reliably detect a liquid consumption status by detecting the liquid surface even in the case that liquid inside the liquid container rolls and bubbles.
Furthermore, it is still another object of the present invention to provide a liquid container, the piezoelectric device of which can reliably detect a liquid consumption status even in the case that the liquid container tilts or fell down because the gas does not contacts with the piezoelectric device.
Furthermore, it is still another object of the present invention to provide a liquid container capable of reliably detecting a liquid consumption status in the liquid container even if the piezoelectric device is mounted on the upper side of the liquid surface in the liquid container.
Furthermore, it is still another object of the present invention to provide a liquid container which does not need to be mounted on the accurate position, in other words, the mounting position of the piezoelectric device on the liquid container can be freely designed.
These objects are achieved by combinations described in the independent claims. The dependent claims define further advantageous and exemplary combinations of the present invention.
According to an aspect of the present invention, there is provided a liquid container which may comprise: a housing containing therein liquid; a liquid supply opening formed in the housing for withdrawing the liquid from the housing; a liquid sensor mounted on the housing for detecting a level of the liquid which is variable in accordance with a consumption of the liquid; and a first partition wall extending in an interior of the housing and defining the interior of the housing into at least two liquid accommodating chambers which communicate with each other, the liquid accommodating chambers comprising: an air-communication side liquid accommodating chamber which communicates with ambient air; and a detection side liquid accommodating chamber in which the liquid sensor is disposed at an upper portion thereof.
The liquid container may further comprises a porous member accommodated within the detection side liquid accommodating chamber. The liquid supply opening may be formed in the air-communication side liquid accommodating chamber. The liquid supply opening may be formed in the detection side liquid accommodating chamber. A volume of the air-communication side liquid accommodating chamber may be different from that of the detection side liquid accommodating chamber. The volumes of the at least two liquid accommodating chambers may decrease from one side wall of the housing to the other opposite wall.
The liquid container may further comprising a second partition wall extending in the detection side liquid accommodating chamber and defining at least two small detection chambers. The second partition wall may be formed with a liquid communication opening at a lower part thereof. The second partition wall may be formed with a liquid communication opening at an upper part thereof. The detection sensor may be disposed on each of the small detection chambers. The volumes of the small detection chambers may be different from each other. The volumes of the at least two small detection chambers may decrease from one side wall of the housing to the other opposite wall.
The detection side liquid accommodating chamber may generate no capillary force for holding the liquid. The small detection chamber may generate no capillary force for holding the liquid. The detection side liquid accommodating chamber may comprise a recessed part formed at a top wall thereof. The liquid sensor may comprise a cavity which opens toward an interior of the housing for holding the liquid. The liquid sensor may comprise a piezoelectric device having a vibrating section, the vibrating section generates a counter electromotive force in accordance with a residual vibration of the vibrating section.
The liquid sensor may detect at least an acoustic impedance of the liquid and detects a liquid consumption status in accordance with the acoustic impedance. The liquid container may be mounted on an ink-jet printing apparatus having a printhead which ejects ink droplets, and the liquid container supplies the liquid contained therein to the printhead through the liquid supply opening. The volume of the detection side liquid accommodating chamber may be equal to or less than half the volume of the air-communication side liquid accommodating chamber. The volumes of the liquid accommodating chambers may decrease from one side wall of the housing to the other opposite wall.
The porous member may comprise a first porous material disposed close to the liquid sensor and a second porous material disposed far from the liquid sensor compared with the first porous material, and the second porous material has a higher liquid-philic characteristics than the first porous material. The liquid sensor may comprise a piezoelectric device having a vibrating section, the vibrating section generates a counter electromotive force in accordance with a residual vibration of the vibrating section. The liquid sensor may detect at least an acoustic impedance of the liquid and detects a liquid consumption status in accordance with the acoustic impedance. The liquid container may be mounted on an ink-jet printing apparatus having a printhead which ejects ink droplets, and the liquid container supplies the liquid contained therein to the printhead through the liquid supply opening.
According to another aspect of the present invention, there is provided a liquid container which may comprise: a housing containing there in liquid; a liquid supply opening supplying liquid to an exterior of the housing; a detection device mounted on the housing, the detection device comprising a piezoelectric element for detecting a liquid consumption status; and a wave absorbing wall extending in an interior of the housing disposed at a place facing the detection device. A gap may be defined between the detection device and the wave absorbing wall. The gap may not generate a capillary force for holding the liquid.
The gap may generate a capillary force which is smaller than a force for holding the liquid. The detection device may comprise a cavity for receiving and holding liquid, the cavity being formed to open toward the interior of the housing. The wave absorbing wall may be secured to and extends from an interior wall of the housing. The detection device may be attached to a first wall of the housing which extends in a vertical direction of the liquid level, and the wave absorbing wall may extend in parallel with the first wall of the housing.
The detection device may be attached to a bottom wall of the housing, and the wave absorbing wall may extend in parallel with the liquid level. The wave absorbing wall may extend in an inclined direction with respect to the liquid level. The wave absorbing wall may extend from a side wall of the housing which is perpendicular to the liquid level. The a capillary force may be generated between at least a part of the internal wall and an inner wall of the housing. The wave absorbing wall may comprise a bending section which is formed by bending at least a part of an edge of the wave absorbing wall toward a wall on which the detection device is mounted, and a gap defined by the bending section and the detection device generates a capillary force while a gap defined by the wave absorbing wall and the detection device does not generate a capillary force.
The wave absorbing wall may comprise a plurality of wave absorbing wall pieces, and at least one of the plurality of wave absorbing wall pieces may extend from a side wall of the housing which is perpendicular to the liquid level. The detection device may comprise a vibrating section which generates a counter electromotive force in accordance with a residual vibration of the vibrating section. The liquid container may be mounted on an ink-jet printing apparatus having a printhead which ejects ink droplets, and the liquid container may supply the liquid contained therein to the printhead through the liquid supply opening.
According to the other aspect of the present invention, there is provided a liquid container may comprise: a housing containing therein liquid; a liquid supply opening formed in a wall of the housing for withdrawing the liquid to an exterior; a detection device mounted on the housing, the detection device comprising a piezoelectric element for detecting a liquid consumption status; and a porous member disposed within the housing in the vicinity of the detection device. The detection device may contact the porous member. A gap may be defined between the porous member and the detection device.
The detection device may comprise a cavity and a vibrating section which contacts the liquid through the cavity, and the porous member is disposed in the cavity. A capillary force of the porous member may be smaller than a force which holds the liquid. The detection device may comprise a base plate, a vibrating portion and a through hole formed in the base plate, and the porous member covers at least a part of the through hole. The detection device may further comprise a groove connecting with the through hole, and the porous member is disposed on the groove. The detection device and the porous member may be disposed on a plane where the liquid supply opening is formed.
The detection device may comprise a vibrating section which generates a counter electromotive force in accordance with a residual vibration of the vibrating section, and the detection device detects the liquid consumption status in accordance with the counter electromotive force. The detection device may comprise a piezo electric element and a mounting structure unitarily formed with the piezoelectric element, and the mounting structure is attached to the housing. The liquid container may be mounted on an ink-jet printing apparatus having a printhead which ejects ink droplets, and the liquid container supplies the liquid contained therein to the printhead through the liquid supply opening.
This summary of the invention does not necessarily describe all necessary features of the present invention. The present invention may also be a sub-combination of the above described features. The above and other features and advantages of the present invention will become more apparent from the following description of embodiments taken in conjunction with the accompanying drawings.